Agricultural implements for opening furrows in the ground and depositing seed therein are well known. One such agricultural apparatus is disclosed in U.S. Pat. No. 7,216,596 B2, which is incorporated by reference herein. Such implements can form a plurality of furrows extending longitudinally along the direction of travel of the implement over the ground. Each furrow is formed by a disk drill that is rotatably mounted on the implement and cuts into the ground as the implement passes through the field. The disk drill may be disposed at an angle relative to the direction of travel, and also may be disposed at an angle relative to a direction normal to the ground over which it traverses (e.g., vertical, relative to a horizontally flat field). On one such implement design, such disk drills are arranged in pairs laterally across the implement and have one soil packing wheel disposed behind each pair of disks. In such a pair of these disks, the disks have the same diameter and are disposed in a mirror-image orientation, side-by-side relative to one another.
In the twin disk drill designs such as illustrated in U.S. Pat. No. 7,216,596, the disks are paired laterally across the implement, with the two disks of each pair being mounted in mirror image relation to one another. The two paired disks are directly opposed and squeeze soil and residue together as they rotate and pass through the ground. In certain soil types and moisture conditions, soil and residue will be held between the disks as they rotate and then released so that the soil and residue are deposited in front of the disks. This results in a non-uniform seed row with uneven depths of seed placement.